4. Are in good health, as determined by vital signs (oral temperature, pulse and blood pressure), medical history and targeted physical examination based on medical history to ensure any existing medical diagnoses or conditions are stable (Stable chronic medical condition - no change in prescription medication, dose, or frequency of medication in the last 3 months and health outcomes of the specific disease are considered to be within acceptable limits in the last 6 months. Any change that is due to change of health care provider, insurance company etc., or that is done for financial reasons, as long as in the same class of medication, will not be considered a violation of this inclusion criterion. Any change in prescription medication due to improvement of a disease outcome will not be considered a violation of this inclusion criterion.) Subjects may be on chronic or as needed (prn) medications if, in the opinion of the site principal investigator or appropriate sub-investigator, they pose no additional risk to subject safety or assessment of reactogenicity and immunogenicity. Note: Topical, nasal, and inhaled medications; vitamins; and contraceptives are permitted with the exception of high dose inhaled steroids (see exclusion criteria #13).